Tools of Environmental Science Chapter 2

Objectives List and describe the steps of the experimental method. Describe why a good hypothesis is not simply a guess. Describe the two essential parts of a good experiment. Describe how scientists study subjects in which experiments are not possible. Explain the importance of curiosity and imagination in science.

Experimental Method - a series of steps that scientists worldwide use to identify and answer questions. 1) Observation 2) Hypothesis 3) Perform an experiment 4) Organize and analyze data 5) Draw conclusions 6) Repeat experiment 7) Communicate results

 Experimental method begins when someone makes an observation and has a questions about what was observed.  Why are my plants wilting? Experimental Method

Step #1: Observation  A piece of information we gather using our senses – sight, hearing, smell, and touch  Can be represented with  Descriptions  Drawings  Photos  Measurement  Observations lead to questions  I see my plants bent over and turning brown. Why is my plant wilting?

Step #2: Form a Hypothesis  Hypothesis – a testable idea or explanation that leads to a scientific investigation  Used to answer a specific question about an observation  My plant is not getting enough water.

Step #3: Experiment  A procedure designed to test a hypothesis under controlled conditions  Should determine cause and effect relationships  I will water one plant on a regular basis and not water the one next to it.

Step #3: Experiments  In order to determine cause and effect experiments must have:  A single variable that we are testing  Ex: water  A control group - to serves as the standard of comparison  Ex: the plant with no water  Experimental group – condition with the new variable  Ex: plant that gets water

The independent, or manipulated variable, is a factor that’s intentionally changed by the experimenter. Ex: water The dependent, or responding variable, is the factor that may change as a result of changes made in the independent variable. Ex: health of the plant, degree of wilting All other factors and environmental conditions in the experiment must remain the same. They are the constants. Ex: soil, pot, room temperature Step #3: Experiment

Step #4: Analyze Data  Data – gathered information, usually in a numeric form.  Data is put into graphs and tables for better understanding

Step #5: Conclusion  Determine the results of your study by analyzing their data and comparing the results with their predictions and hypothesis.  The plant that was watered did better than the one with no water.

Step #6: Repeat Experiment  Always repeat your experiement  WHY???

Step #7: Communicate results  Your study is not finished until you have shared your results

Correlation Method  When experimenting is unethical or impossible to test we can use correlations.  Correlation – an association between two or more events  Does not prove cause and effect relationships  Ex: There is a correlation between TV watching and childhood violence  Can you think of other reasons for this correlation?

Scientific State of Mind  Curiosity  Skepticism – don’t believe everything you are told  Openness to new ideas  Honesty  Imagination and creativity

Section 2 - Objectives  Explain how scientists use statistics.  Explain why the size of a statistical sample is important.  Describe three types of models commonly used by scientists.  Explain the relationship between probability and risk.  Explain the importance of conceptual models and mathematical models.

Section 2: Statistics and Models  Statistics – the collection and classification of data in the form of numbers  They help organize data by:  Summarizing  Characterizing  Analyzing  comparing

Statistical Vocab  Mean – average  Probability – the chance that something will happen  Sample – a group selected to represent a larger population  Risk – the probability of an unwanted outcome  Distribution – shown on a graph

What are you afraid of?  Rank the following in order from mostly likely to die from to least likely:  Venomous bite  Airplane crash  Drowning  Cancer  Car accident  Falling down  Gunshot  Fireworks accident  Heart disease  Lightning

How did you do?  Heart disease1 in 5  Cancer1 in7  Car accident1 in 100  Falling down1 in 246  Gunshot1 in 325  Drowning1 in 8,942  Airplane crash1 in 20,000  Lightning1 in 83,930  Venomous Bite1 in 100,000  Fireworks1 in 615,488

Can you name some models? Not of the human type!

Models – representations of objects or systems  Physical models – three dimensional, you can touch them. Ex: globe  Graphical model – maps, charts, graphs  Conceptual model – a verbal or graphical explanation of how a system works or is organized. Ex: atom  Mathematical model – equations that represent the way a system or process works. Ex: earths rotation

Class Work  Ch. 2  Section 1 & 2 Review  Page 39 Questions: 1-4  Page 46 Questions: 1-3

Section 3 - Objectives  Describe three values that people consider when making decisions about the environment.  Describe the four steps in a simple environmental decision-making model.  Compare the short-term and long-term consequences of two decisions regarding a hypothetical environmental issue.

Section 3: Making Informed Decisions  Values – principles or standards we consider important Name some of your values….

Section 3: Making Informed Decisions  Decision-making model – a conceptual model that provides a systematic process for making decisions

Section 3: Making Informed Decisions  Read the Case Study-page and answer questions  Section 3 review Pg. 51 # 1&2